卡住訪問非最終變量？

Question

我只是測試了我的代碼，我試圖做到這一點，當我點擊「推」按鈕，第一個textArea打印出「你好」。

，但我不斷收到此錯誤：無法指非最終變量textarea的不同方法

這裏定義的內部類裏面是我的代碼：

import java.awt.BorderLayout; 

公共類WindowBuilderTest擴展的JFrame {

private JPanel contentPane; 
private JTextField textField; 

/** 
* Launch the application. 
*/ 
public static void main(String[] args) { 
    EventQueue.invokeLater(new Runnable() { 
     public void run() { 
      try { 
       WindowBuilderTest frame = new WindowBuilderTest(); 
       frame.setVisible(true); 
      } catch (Exception e) { 
       e.printStackTrace(); 
      } 
     } 
    }); 
} 

/** 
* Create the frame. 
*/ 
public WindowBuilderTest() { 
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
    setBounds(100, 100, 400, 400); 
    contentPane = new JPanel(); 
    contentPane.setBorder(new EmptyBorder(5, 5, 5, 5)); 
    setContentPane(contentPane); 
    GridBagLayout gbl_contentPane = new GridBagLayout(); 
    gbl_contentPane.columnWidths = new int[]{90, 92, 95, 95, 0}; 
    gbl_contentPane.rowHeights = new int[]{64, 74, 83, 74, 12, 0}; 
    gbl_contentPane.columnWeights = new double[]{1.0, 1.0, 1.0, 1.0, Double.MIN_VALUE}; 
    gbl_contentPane.rowWeights = new double[]{1.0, 0.0, 0.0, 1.0, 1.0, Double.MIN_VALUE}; 
    contentPane.setLayout(gbl_contentPane); 

    JTextArea textArea = new JTextArea(); 
    textArea.setEditable(false); 
    GridBagConstraints gbc_textArea = new GridBagConstraints(); 
    gbc_textArea.gridheight = 2; 
    gbc_textArea.insets = new Insets(0, 0, 5, 5); 
    gbc_textArea.fill = GridBagConstraints.BOTH; 
    gbc_textArea.gridx = 0; 
    gbc_textArea.gridy = 0; 
    contentPane.add(textArea, gbc_textArea); 

    JLabel lblstack = new JLabel("<-- Stack"); 
    GridBagConstraints gbc_lblstack = new GridBagConstraints(); 
    gbc_lblstack.gridheight = 2; 
    gbc_lblstack.anchor = GridBagConstraints.WEST; 
    gbc_lblstack.insets = new Insets(0, 0, 5, 5); 
    gbc_lblstack.gridx = 1; 
    gbc_lblstack.gridy = 0; 
    contentPane.add(lblstack, gbc_lblstack); 

    JLabel lblNewLabel = new JLabel("Result -->"); 
    GridBagConstraints gbc_lblNewLabel = new GridBagConstraints(); 
    gbc_lblNewLabel.anchor = GridBagConstraints.EAST; 
    gbc_lblNewLabel.gridheight = 2; 
    gbc_lblNewLabel.insets = new Insets(0, 0, 5, 5); 
    gbc_lblNewLabel.gridx = 2; 
    gbc_lblNewLabel.gridy = 0; 
    contentPane.add(lblNewLabel, gbc_lblNewLabel); 

    JTextArea textArea_2 = new JTextArea(); 
    textArea_2.setEditable(false); 
    GridBagConstraints gbc_textArea_2 = new GridBagConstraints(); 
    gbc_textArea_2.gridheight = 2; 
    gbc_textArea_2.insets = new Insets(0, 0, 5, 0); 
    gbc_textArea_2.fill = GridBagConstraints.BOTH; 
    gbc_textArea_2.gridx = 3; 
    gbc_textArea_2.gridy = 0; 
    contentPane.add(textArea_2, gbc_textArea_2); 

    textField = new JTextField(); 
    GridBagConstraints gbc_textField = new GridBagConstraints(); 
    gbc_textField.anchor = GridBagConstraints.SOUTH; 
    gbc_textField.gridwidth = 2; 
    gbc_textField.insets = new Insets(0, 0, 5, 5); 
    gbc_textField.fill = GridBagConstraints.HORIZONTAL; 
    gbc_textField.gridx = 1; 
    gbc_textField.gridy = 2; 
    contentPane.add(textField, gbc_textField); 
    textField.setColumns(10); 

    JLabel lblenterInteger = new JLabel("<-- Enter Integer"); 
    GridBagConstraints gbc_lblenterInteger = new GridBagConstraints(); 
    gbc_lblenterInteger.anchor = GridBagConstraints.SOUTHWEST; 
    gbc_lblenterInteger.insets = new Insets(0, 0, 5, 0); 
    gbc_lblenterInteger.gridx = 3; 
    gbc_lblenterInteger.gridy = 2; 
    contentPane.add(lblenterInteger, gbc_lblenterInteger); 

    JButton btnNewButton = new JButton("Push"); 
    btnNewButton.addActionListener(new ActionListener() { 
     public void actionPerformed(ActionEvent arg0) { 

      String TEST = "Hello"; 

      textArea.setText(TEST); 

     } 
    }); 
    GridBagConstraints gbc_btnNewButton = new GridBagConstraints(); 
    gbc_btnNewButton.fill = GridBagConstraints.BOTH; 
    gbc_btnNewButton.insets = new Insets(0, 0, 5, 5); 
    gbc_btnNewButton.gridx = 0; 
    gbc_btnNewButton.gridy = 3; 
    contentPane.add(btnNewButton, gbc_btnNewButton); 

    JButton btnNewButton_1 = new JButton("Pop"); 
    GridBagConstraints gbc_btnNewButton_1 = new GridBagConstraints(); 
    gbc_btnNewButton_1.fill = GridBagConstraints.BOTH; 
    gbc_btnNewButton_1.insets = new Insets(0, 0, 5, 5); 
    gbc_btnNewButton_1.gridx = 1; 
    gbc_btnNewButton_1.gridy = 3; 
    contentPane.add(btnNewButton_1, gbc_btnNewButton_1); 

    JButton btnNewButton_2 = new JButton("Peek"); 
    GridBagConstraints gbc_btnNewButton_2 = new GridBagConstraints(); 
    gbc_btnNewButton_2.fill = GridBagConstraints.BOTH; 
    gbc_btnNewButton_2.insets = new Insets(0, 0, 5, 5); 
    gbc_btnNewButton_2.gridx = 2; 
    gbc_btnNewButton_2.gridy = 3; 
    contentPane.add(btnNewButton_2, gbc_btnNewButton_2); 

    JButton btnNewButton_3 = new JButton("Exit"); 
    GridBagConstraints gbc_btnNewButton_3 = new GridBagConstraints(); 
    gbc_btnNewButton_3.fill = GridBagConstraints.BOTH; 
    gbc_btnNewButton_3.insets = new Insets(0, 0, 5, 0); 
    gbc_btnNewButton_3.gridx = 3; 
    gbc_btnNewButton_3.gridy = 3; 
    contentPane.add(btnNewButton_3, gbc_btnNewButton_3); 

    JTextArea textArea_1 = new JTextArea(); 
    textArea_1.setEditable(false); 
    GridBagConstraints gbc_textArea_1 = new GridBagConstraints(); 
    gbc_textArea_1.gridwidth = 4; 
    gbc_textArea_1.fill = GridBagConstraints.BOTH; 
    gbc_textArea_1.gridx = 0; 
    gbc_textArea_1.gridy = 4; 
    contentPane.add(textArea_1, gbc_textArea_1); 
} 

}

Answer 1

然後改變第是：

JTextArea textArea = new JTextArea(); 

這樣：

final JTextArea textArea = new JTextArea(); 

這僅僅是你必須使用anonymous inner classes當做某事;）